1. Field of the Invention
This invention relates to a heat transfer device, more particularly to a flexible heat transfer device.
2. Description of the Related Art
Various types of heat transfer devices for dissipating heat are available. A typical heat transfer device is the heat pipe which has the best cooling ability and reliability, the lowest noise and the most compact volume when compared to the other types of heat transfer devices, such as water cooling heat exchangers, natural convection coolers, force convection coolers, etc. However, because the heat pipes are made of copper, aluminum or stainless steel rigid tubes with a circular cross section, they must be inserted into the heat source or provided with a carrier which serves as an auxiliary contact means between the heat pipes and the heat source in order to increase the effective contact area for heat dissipation. The carrier reduces the heat dissipation efficiency of the heat pipe. FIG. 1 is a perspective schematic view illustrating the heat dissipation of a circuit member by utilizing a heat pipe. The power IC 31 contacts the heat pipe 235 by means of a carrier 33 with a curved contact face. A plurality of heat dissipation plates 37 are provided on the heat pipe 37 in order to achieve the heat dissipation process. Therefore, although the heat pipe 35 has an excellent heat dissipation effect, the heat resistant of the carrier 33 and the complicated design greatly reduce the utility of the heat pipe in practice. The limited contact areas of the heat pipes and the heat sources, and the rigidity of the heat pipes cause the heat dissipation design work to be difficult if heat pipes are to be used. FIG. 2 is a schematic view of another embodiment of the heat pipes. In this embodiment, the heat from the printed circuit boards 41 and 42 is transferred to a heat dissipation plate 45 by means of specially designed bent heat pipes, 43 and 44. In addition, if the heat source is an electronic element, the metal heat tubes must be insulated. This increases the complexity and manufacturing cost of the heat pipes. Therefore, the heat pipes are often used in high precision or high technology equipments. The heat pipes are rarely used in ordinary industry equipments.